bit.addEventListener("click",function () {
  var user = document.getElementById("user");
  var pwd = document.getElementById("pwd");
  if (user.value ==="admin" && pwd.value ==="123") {
      alert("登录成功");
      window.location.href="http://47.116.207.219/homePage";
  } else {
      pwd.value="";
      alert("账号或密码错误")
      }
  })
